Refrigerator insulation



y 26, 1953 R. E. DEUTGEN REFRIGERATOR INSULATION 2 Sheets-Sheet 1 Filed Oct. 25, 1945 INVENTOR WWW 444:4 ATTORNEY y 26, 3 R. E. DEUTGEN REFRIGERATOR INSULATION Filed 001;. 23, 1945 '2 Sheets-Sheet 2 i I 1 E I INVENTOR 145164. A; ATJ'ITORNEY Patented May 26, 1953 REFRIGERATOR INSULATION Ragnar Edvard Deutgen, Stockholm, Sweden, assignor to Aktiebolaget Elektrolux, Stockholm, Sweden, a corporation of Sweden Application October 23, 1945, Serial No. 623,983 In Sweden November 6, 1944 23 Claims.

This invention relates to cooling compartments, refrigerators, cooling display cases and the like having a chamber cooled by a cold source, and has for its object to provide an improvement for simplifying the heat-insulation surrounding the cooling chamber and the utilization of cheaper material for this insulation.

It is known that the requirements of heatinsulation for refrigerator cabinets and other storage compartments cooled by a cold source'are different from those of heated chambers, heated cabinets and the like. This difference is due to the fact that the moisture of the outside atmosphere penetrates into the insulation by the effect of the cold source, thereby causing a continuous deterioration and decrease in the insulating capacity of the material.

Therefore, it has been necessary to utilize material resistant against moisture for insulating cooling compartments, or to take special measures in order to effect ventilation of the insulation in such a way that the condensation of moisture in the atmosphere will be forced to take place within the cooling chamber itself. Finally, attempts have been made to solve the problem by utilizing an hermetically closed insulation safe from the effect of the outside atmosphere.

This restriction in the choice of insulating material necessitated by the problem of moisture condensation has prohibited the use of available inexpensive and effective heat-insulating materials, which for other reasons are preferable to those of the water resistant type.

In accordance with the invention the possibility of using better materials for insulation is improved. This is accomplished by providing about a cooling chamber a layer of insulating material impervious to moisture, the thickness of which is preferably limited so that the temperature of the outer surface thereof only exceeds by a few degrees the lowest temperature produced in the cooling chamber. In addition, such water-proof insulating layer is surrounded by a second insulating layer which is permeable to air and in free communication with the cooling chamber through ventilating channels.

Fig. 3 is a fragmentary vertical sectional view of a refrigerator or cooling cabinet illustrating another embodiment of the invention;

Referring to Fig. 1, the invention i embodied in a refrigerator which may be operated, for example, by absorption refrigerating apparatus of the inert gas type, not shown. The evaporator of such a primary refrigerating apparatus is heatconductively connected in any suitable manner (not shown) to a secondary heat transfer system having a cooling element Ill. The cooling element In is formed of piping which is heat-conductively attached to the inner liner l I of the refrigerator, as by welding, forexample, such inner liner being suitably formed in a single piece from a sheet of steel plate. The inner liner and the cooling element is are supported by a frame [2 formed of wood or other suitable insulating material to which is also secured the outer wall member l3 of the refrigerator, thereby insulating the inner liner from the outer wall member which is also formed of sheet metal. The inner liner I I defines a cooling space ll having an access opening which is adapted to be closed by a thermally insulated cover l5.

Depending upon the temperature produced by the secondary heat transfer system, water or ice would form on the piping Ill and/ or on the outer surface of the inner liner ll if no special provisions are taken, and the resulting moisture would gradually destroy all of the insulation of the refrigerator cabinet. In order to avoid this, the thermal insulation provided in accordance with the invention is divided into two layers, the inner insulating layer M of which is formed of a material substantially impervious and resistant to moisture, such as cork, for example, which is partly impregnated and/or covered with a waterresistant impregnating substance, like asphalt.

Such impregnating substance is also effective to seal the seams 01' joints formed in the insulating layer, so that water vapor present in atmos- The invention, together with the objects and advantages thereof, will become apparent from the following description taken in connection with the accompanying drawing forming a part of this specification, and of which:

Fig. l'is a vertical sectional view of a refrigerator or cooling cabinet embodying the invention;

Fig. 2 is an enlarged fragmentary sectional view of the refrigerator shown in Fig. 1 to illustrate details more clearly; and

pheric air cannot penetrate into or through the material. In this way the space I6 occupied by the cooling element or piping I0 is hermetically sealed between the inner liner H and insulating layer [4 from penetrating water vapor. The thermal conductive properties and the cost of such a water-resistant and hermetically sealed insulating layer [4 are such that it is advantageous to keep the thickness of this layer as small as possible.

According to the invention the inner insulating layer [4 is desirably of such thickness that the temperature maintained at the outer surface thereof will only exceed by a few degrees the lowest temperature prevailing in the cooling chamber l'l. About the inner insulating layer 14 is provided a main insulation layer [B which is disposed between the inner layer M and the outer wall member [3 of the refrigerator cabinet.

The outer insulating layer Iii may be formed of any suitable insulating material, such as glass-wool, corrugated cardboard or other paper, for example, which does not necessarily need to be hermetically enclosed although it desirably should be protected as much as possible from water vapor penetrating therein. This is accomplished by suitably forming the outer shell or wall member [3 and providing a good connection thereto of the outer edge portion of the member it which is located about the access opening into the cooling space ll. The inner edge portion of the member 19 is fixed to the insulating frame [2 to minimize heat transfer between the inner liner I1 and outer wall member l3.

Theouter layer 18 of insulation should be sufflciently porous so that it is permeable to a gas like air, for example, with the different parts of the insulation providing relatively free communication for flow of gas therethrough. In the event moisture is formed in the porous insulating material it is vitally necessary, in or der to effect removal of such moisture from the insulating material in the form of water vapor,

that air containing such water vapor can readily how or diffuse within the material.

In the refrigerator cabinet of 1 air circulates between the insulation layer it and the cooling space I'! through ventilating channels or passageways 2!? which extend through openings formed in the upper part of the inner liner ii and inner insulation layer 1'4. Any Water vapor present in the insulation layer It is transferred and conveyed into the cooling space I! by the air passin through this insulation layer.

'In order to avoid leakage of air into the insulating layer 14 and into the space 16, the passageways 2B are formed of pipes '22 which are secured in an air-tight manner, as by asphalt for example, about the openings in the inner liner ll and peripheral surfaces or the apertures in the insulation layer M. Also, bushings 23 are inserted into the open ends of the pipes 22 terminating at the inner liner 1]. A fine mesh screen 25 is provided in each bushing 23 to prevent foreign matter passing into the outer insulation layer 18, as shown most clearly in Fig. '2.

When "it is desired to provide an inner insulation layer I of a material like glass wool, for example, which cannot be readily formed into self-su'staming or stable boards or sheets, the principles of the invention can be carried out in the manner diagrammatically shown in Fig. '3. In Fig. 3, in which parts similar to those illustrated in Figs. 1 and 2 are designated by the same reference numerals, the inner in'su-- lati'on layer 14, which may be formed o"f --glass wool 'or the like, for example, is positioned between the inner liner ii and a protective hood or partition to comprising a number of platel'ik'e members securely joined together, as bysoldering or brazing. The protective hood to is hermetically fixed to a wooden frame '31 by screws and asphalt.

Between the protective hood 3i] andouter insulation layer 18 are provided spacers or inserts 3 2 formed 'of woodor other suitable heat of Fig. 3.

insulating material. In the embodiment being described, the passageways 20 establish communication between the cooling space and a passage 33 formed between the inner and outer insulation layers l4 and I 8, thereby simplifying the manner in which air fromthe cooling space can pass through the different parts of the outer insulation layer I8. The pipes providing the passageways 2c are hermetically sealed to the protective hood 30 at the regions of the openings therein as well as to the inner liner 1 I, as by asphalt, for example.

In view of the foregoing, it should be apparout that the principles of the invention can be practiced in many different ways within its basic concept and hence is not to be limited to the embodiments illustrated and just described. It should be understood that the construction and shape of both inner and outer insulation layers, and the disposition of the ventilation channeis, will depend upon a number of factors ineluding the size of the cooling chamber which may vary between wide limits.

Regarding the ratio of the thickness of the inner insulation layer to the outer insulation layer, it may be stated that at least for refrigerator cabinets and cooling boxes and the like, the insulating effect or value of the inner insulation layer 14 should be about one-fifth and less than a major portion of the total insulating effect or value of both insulation layers. This ratio will vary, of course, when consideration is given to a number of factors including the temperature at which the cooling space to be maintained and the atmospheric con ditions under which apparatus of the invention is intended to be used.

While the outer wall member 13 does not necessarily need to be hermetically sealed and absolutely air-tight to protect the outer insulation layer {'8 from moisture laden atmospheric air, it should provide an enclosure of such a character that unduly large quantities of water vapor cannot penetrate into the outer insulation "layer and remain therein. However, such a quantity of water vapor may penetrate into the outer insulation layer it which can be efrelatively transferred and conveyed therefrom into the cooling space by movement oi air through the passageways 2b. The rate at which water vapor can be removed in this way from the outer insulation layer "It will depend, of course, upon its physical characteristics and the extent to which it is permeable to air.

The air passageway 33 in the embodiment of Fig. '3 not only simplifies the removal of water vapor from the outer insulation layer 18 but also promotes and facilitates the removal of condensed moisture which may accidentally pass into the passageways or ventilating channels 2U. This is especially true, for example, in the case-of the passageways -formed at the bottom of the cooling space in the embodiment While these bottom passageways may be closed by suitable stoppers or closure members when defrosting or cleaning is instigated, water may still pass into such passageways when the latter inadvertently are not closed.

While theinvention is susceptible of many applications, it is particularly useful when the cooling element or evaporator is positioned at the outer wall surface of a cooling space at which region the lowest temperature is prodnced as in the embodiments shown-and described above. Moreover, the cooling element can'be positioned in thermal conductive relation with the outer surface of the inner liner without encountering any problems due to condensation of moisture. With such an arrangement a maximum amount of space is made available in the cooling chamber while efficient refrigeration is effected, and at the same time the cooling chamber is easily kept clean and sanitary.

I claim:

1. Refrigeration apparatus including structure defining a space to be cooled, cooling means to effect cooling of said space, a first body of material disposed about said space which is substantially impervious to moisture and provides such an insulating effect that the outer surfacethereof during normal operation of said cooling means will be maintained at a temperature exceeding by only a few degrees the lowest temperature produced in said space, and means including a body of thermal insulation disposed about said first body which is permeable to air and in communication with said space to permit movement of air therebetween.

2. Refrigeration apparatus including structure defining a space to be cooled, cooling means to effect cooling of said space, a first body of material disposed about said space constructed and arranged to be substantially impervious to moisture and provide such a thermal conductive path that the outer surface thereof during normal operation of said cooling means will be maintained at a temperature exceeding by only a few degrees the lowest temperature produced in said space, and an enclosed body of thermal insulation disposed about said first body which is sufficiently porous to permit air containing water vapor to pass therethrough, said body of thermal insulation being in communication with said space to permit movement of air therebetween.

3. Refrigeration apparatus including an inner liner and an outer wall member having a gap therebetween, said inner liner defining a space to be cooled, cooling means to effect cooling of said space, thermal insulation in said gap comprising an inner body of insulating material constructed and arranged to be substantially impervious to moisture and an outer body of insulating material disposed about said first body which is permeable to air, and means embodied in the apparatus to promote movement of air between said space and said outer body of material.

4. Refrigeration apparatus including an inner liner and an outer wall member having a gap therebetween, said inner liner defining a cooling space, cooling means to effect cooling of said space, and thermal insulation in said gap comprising an inner body of material constructed and formed to be substantially impervious to moisture and an outer body of material disposed about said inner body which is permeable to air and in communication with said space to permit movement of air therebetween, said inner body having an insulating effect which provides less than a major portion of the total insulating effect of both said inner and outer bodies.

5. Refrigeration apparatus comprising a cabinet including an inner liner and an outer wall member having a gap therebetween, said inner liner defining a storage compartment, cooling means to effect cooling of said compartment, thermal insulation in said gap comprising a self sustaining inner body of material overlying said inner liner constructed and arranged to be substantially impervious to moisture and provide such an insulating effect that the outer surface thereof during normal operation of said cooling 6 means will be maintained at a temperature exceeding by only a few degrees the lowest temperature produced in said compartment, and an outer. body of insulating material disposed about said inner body which is permeable to air, and means providing passageways establishing communication between said compartment and said outer body of material to permit movement of air therebetween.

6. Refrigeration apparatus including structure defining a space to be cooled, cooling means to effect cooling of said space, an inner layer of thermal insulation disposed about said space constructed and arranged to be water-tight and gastight, and an enclosed outer layer of thermal insulation permeable to air which surrounds said inner layer and is spaced therefrom to provide a gap between said inner and outer layers, and pas sage means to permit movement of air between said space to be cooled and the gap between said inner and outer layers.

'7. Refrigeration apparatus as set forth in claim 6 in which spacers having poor thermal conductivity are provided to maintain said inner and outer layers in spaced relation.

8. Refrigeration apparatus as set forth in claim 6 in which the insulating effect provided by said inner layer is less than a major portion of the total insulating effect of both said inner and outer layers.

9. Refrigeration apparatus including an inner liner and an outer wall member having a gap therebetween, said inner liner defining a storage compartment, cooling means to effect cooling of said storage compartment, thermal insulation in said gap comprising an inner body of material constructed and arranged to be substantially impervious to moisture and an outer body of material permeable to air which is disposed about said inner body and spaced therefrom, openings in said inner liner, and means cooperating with the openings and extending through said inner body to provide hermetically sealed passageways between said compartment and the space between said inner and outer bodies of material.

10. Refrigeration apparatus including inner and outer wall members having a gap therebetween, said inner wall member defining a space, cooling means to effect cooling of said space, an inner layer of thermal insulation in said gap which is adjacent to said inner wall member and constructed and arranged to be impervious to moisture, an outer layer of thermal insulation in said gap surrounding said inner layer which is sufficiently porous to permit air containing water vapor to pass therethrough in a general direction parallel to its sides, and means providing air passageways between said space and different re ions of said outer layer.

11. Refrigeration apparatus including an outer wall member and an inner liner having a, gap therebetween, said inner liner defining a space to be cooled, cooling means to effect cooling of said space, an inner layer of material in said gap adjacent to said inner liner constructed and ar ranged to be substantially impervious to mois ture and provide such an insulating effect that the outer surface thereof during normal operation of said cooling means will be maintained at a temperature exceeding by only a few degrees the lowest temperature produced in said space, an outer layer of thermal insulating material in said gap disposed about said inner layer which is permeable to air, and means providing passageways between said space and said outer body of material, said passageways being located to induce natural circulation of air in said gap.

12. Refrigeration apparatus including a metallic wall member defining a space to be cooled, cooling means in thermal conductive relation with said wall member, a first body of material disposed about said space constructed and arranged to be substantially impervious to moisture and provide such an insulating effect that the outer surface thereof during normal operation of said cooling means will be maintained at a temperature exceeding by only a few degrees the lowest temperature produced in said space, and an enclosed body of thermal insulation disposed about said first body which is permeable to air and in communication with said space to permit movement of air therebetween.

l3. Refrigeration apparatus including an outer wall member and an inner metallic liner having a gap therebetween, said inner liner defining a space, cooling means in thermal conductive relation with the outer surface of said inner liner, an inner layer of thermal insulation in said gap which overlies said coolingmeans and is constructed and arranged to be substantially impervious to moisture, an outer layer of thermal insulation in said gap which is disposed about said inner layer and permeable to air, and means embodied in the apparatus to promote circulation of air between said space and said outer layer of thermal insulation.

14. Refrigeration apparatus including an outer wall member and an inner metallic liner having a gap therebetween, cooling means in thermal conductive relation with the outer surface of said inner liner, thermal insulation arranged in said gap comprising an imier layer of insulating material which is adjacent to said inner liner and constructed and arranged to be substantially impervious to moisture and another layer of insu lating material in said gap surrounding said first layer which is permeable to air and in communication with said space to permit movement of air therebetween, said inner layer having an insulating effect which provides less than a major portion of the total insulating effect of both said inner and outer layers.

15. Refrigeration apparatus including an outer wall member and an inner metallic liner having a gap therebetween, said inner liner defining a space to be cooled, cooling means in thermal conductive relation with the outer surface of said inner liner, an inner body of material in said gap adjacent to said inner liner which is substantially impervious to moisture and arranged to hermetically seal said cooling means and pro vide such an insulating effect that the outer surface thereof during normal ope-ration of said cooling means will be maintained at a temperature exceeding by only a few degrees the lowest temperature produced in said space, an outer body of insulating material in said gap which is disposed about said inner body and spaced therefrom and permeable to air, and passageway means between said space to be cooled and the space between said inner and outer bodies of material to permit movement of air therebetween.

l6. Refrigeration apparatus including an inner metallic liner and an outer wall member having a gap therebetween, said inner liner defining a space to be cooled, cooling means in thermal conductive relation with the outer surface of said inner liner, and thermal insulation arranged in said gap comprising an inner layer of insulating ,material constructed and arranged to be substantially impervious to moisture and hermetically seal said cooling means, and an outer layer of insulating material surrounding said inner layer which is sufiiciently porous to permit air containing water vapor to pass therethrough, said space to be cooled being in communication with said outer layer to permit movement of air therebetween.

1'7. Refrigeration apparatus including inner and outer wall members having a gap therebetween, said inner wall member defining a space having a bottom and an upstanding side Wall terminating at an access opening adapted to be closed by a removable insulated closure member, cooling means to effect cooling of said space, thermal insulation in said gap comprising a first body of insulating material adjacent to said inner wall member constructed and arranged to be impervious to moisture and a second body of insulating material disposed about said first body which is permeable to air, said inner wall member having openings at least in the upper part of the side wall thereof, and means cooperating with the openings to provide hermetically sealed passageways for air between said space and said second body of insulating material.

18. Refrigeration apparatus including inner and outer wall members having a gap therebetween, said inner wall member defining a storage compartment having a bottom and an upstanding side wall terminating at an access opening adapted to be closed by a removable insulated closure member, cooling means to effect cooling of said space, thermal insulation in said gap comprising a first body of insulating material adjacent to said inner wall member constructed and arranged to be impervious to moisture and a second body of insulating material which is disposed about said first body and spaced therefrom and permeable to air, said inner wall member ha-vins openings at least in the upper part of the side wall and in the bottom, means cooperating with the openings to provide hermetically sealed passageways for air between said compartment and the space between said first and second bodies of insulating material, and removable stoppers adapted to close the passages provided at the bottom of said compartment.

19. Refrigeration apparatus including an inner liner and an outer wall member having a gap therebetween, said inner liner defining a space having an access opening adapted to be closed by a closure member, cooling means to effect cooling of said space, thermal insulation in said gap comprising an inner layer of insulating material constructed and arranged to be substantially impervious to moisture and provide an insulating effect to maintain a temperature differential between the outer surface thereof and said liner, and an outer layer of thermal insulation disposed about said inner layer which is permeable to air and in communication with said space to permit movement of said therebetween when the access opening is closed by the closure member.

20. Refrigeration apparatus including an inner liner and an outer wall member having a gap therebetween, said inner liner defining a space having an access opening adapted to be closed by a closure member, cooling means in thermal conductive relation with the outer surface of said inner liner for cooling said space, and thermal insulation in said gap comprising an inner layer of insulating material substantially impervious to moisture constructed and arranged to hermetically seal said cooling means and provide 2 an insulating efiect to maintain a temperature differential between the outer surface thereof and said liner, and an outer layer of insulating material surrounding said inner layer which is permeable to air and in communication with said space to permit movement of air therebetween when the access opening is closed by the closure member.

21. Refrigeration apparatus including structure defining a space to be cooled, cooling means to effect cooling of said space, an inner layer of thermal insulation disposed about said space constructed and arranged to be water-tight and gastight, and an enclosed outer layer of thermal insulation permeable to air which surrounds said inner layer and is in communication with said space to permit movement of air between said space and said outer layer.

22. Refrigeration apparatus including structure defining a space to be cooled, cooling means at the exterior of said space to effect cooling thereof, an inner layer of thermal insulation disposed about said space constructed and arranged to be water-tight and gas-tight and hermetically seal said cooling means, and an enclosed outer layer of thermal insulation permeable to 'air which surrounds said inner layer and is in communication with said space to permit movement of air between the latter and said outer layer.

23. Refrigerating apparatus comprising, a

cabinet casing, a liner within said casing forming a storage compartment having an access opening to the compartment, a door closing said access opening, a refrigerant evaporator in heat conducting relationship with said liner on the outer surface thereof, a sealing casing enclosing said liner and evaporator Within said cabinet casing, imperforate heat breaker strips spanning adjacent edges of said liner and sealing casing at the door opening, heat insulation interposed between said cabinet casing and said sealing casing, heat insulation interposed between said sealing casing and said liner imbedding said evaporator, and a passage through both said liner and said sealing casing communicatively connecting the space between said cabinet casing and sealing casing with said storage compartment.

RAGNAR EDVARD DEUTGE'N.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,541,797 Dennison June 16, 1925 2,084,883 Atchison June 22, 1937 2,244,005 Gustin et a1 June 3, 1941 2,304,757 Arthur Dec. 8, 1942 2,324,971 Woodward July 20, 1943 2,338,452 Munters Jan. 4, 1944 2,432,042 Richard Dec. 2, 1947 

